Technical Field
The present invention relates to a semiconductor device, a method of manufacturing the same and a power converter
Description of the Related Art
A technique of forming an electrode having ohmic properties (ohmic electrode) on a semiconductor layer has been known as the method of manufacturing a semiconductor device (semiconductor element) (for example, JP H07-221103A). In general, the ohmic electrode formed on the semiconductor layer is required to reduce the contact resistance, while ensuring the adhesion to the semiconductor layer.
JP H07-221103A describes stacking a plurality of electrode layers and subsequently processing the stacked electrode layers by heat treatment (annealing process, annealing to form the ohmic electrode.
In the ohmic electrode formed by heat treatment of the plurality of electrode layers, the metals of the respective electrode layers are alloyed by heat treatment. The ohmic electrode is thus unlikely to have sufficient resistance to etching. The technique described in JP H07-221103A has not fully taken into account exposure of the ohmic electrode to etching. The contact resistance of the ohmic electrode to the semiconductor layer is thus likely to increase. There is accordingly a need for a technique that avoids an increase in contact resistance of the ohmic electrode by etching. Other needs with regard to the semiconductor device include cost reduction, miniaturization, easy manufacture, resource saving, improvement of usability and improvement of durability.